In automobiles, various electric components and electronic devices are mounted, and electric wires (in other words, wire harnesses) are arranged between the electric components (electronic devices) to transmit electric power, control signals, and the like. For such various electric wires, there has been proposed to give, for each electric circuit, an identification mark to distinguish a corresponding electric wire (see Patent Document 1). According to a covered electric wire disclosed in Patent Document 1, a plurality of kinds of identification marks, different in color and size from one another, are printed intermittently along an axial direction (i.e., longitudinal direction) on an external surface of a covering portion.
Among the automobiles, especially in electric cars or hybrid cars, devices such as a motor, a battery, an inverter, and the like are electrically connected with one another through electric wires serving as power lines. By the electric wires, DC power from the battery is transmitted to the inverter, AC power obtained by inversion in the inverter is supplied to the motor, and the motor is driven by the supplied power. In this manner, the power supplied to the motor has a high voltage, and order to distinguish a high voltage electric wire, an insulation coating (i.e., sheath) of the electric wire or an exterior member (such as a corrugated tube or an aluminum pipe) may be entirely colored in an identification color (e.g., in orange) (see Patent Document 2).
In an electric car or a hybrid car, a battery may be placed below a seat or in a trunk room at a rear part of the vehicle while an inverter and a motor are placed in an engine room at a front part of the vehicle. In this case, an electric wire (i.e., the power line) connecting the battery and the inverter to each other may be arranged beneath a floor of the vehicle (see Patent Document 3). The electric wire arranged beneath the floor is typically covered by an exterior member to protect the electric wire from stones or water splashing during running of the vehicle. In addition, the electric wire may be also covered by an electrically conductive exterior member for shielding so as to prevent electric noise from leaking out from the electric wire to be arranged and prevent external electric noise from being mixed into the electric wire. In this manner, the exterior member is requested to have various functions, such as protecting and waterproofing the electric wire as well as electrically shielding the electric wire, and also requested to have various performances such as keeping the three-dimensionally arranged configuration, improving stability during transportation of the electric wire handling during mounting on a vehicle, and the like.
Patent Document 1: JP 2003-168329 A
Patent Document 2: JP 2009-143326 A
Patent Document 3: JP 2012-125097 A
In an exterior member thus requested to have various performances, a suitable material and a suitable production method are selected. As a result, the following problems arise in distinguishing from other electric wires (or another exterior member) based on its identification color. First, when giving a plurality of kinds of identification marks, different in color and size from one another, intermittently along the longitudinal direction of an elongated exterior member as disclosed in Patent Document 1, a process of coloring the plurality of colors may be complicated and a coloring apparatus may increase in size. Thus, the manufacturing cost may increase. Next, when integrally molding a resin exterior member from a resin material mixed with a coloring agent as disclosed in Patent Document 2, a manufacturing process can be simplified. However, the process cannot be applied to a metal exterior member made of metal, and it is necessary to change the manufacturing process in accordance with the material of the exterior member, which is inefficient. In addition, when coloring an entire external surface of the metal exterior member, plenty of a coloring agent has to be used. Thus, there is another problem that the material cost increases.